3d printers and photocurable polymer and resin based feedstocks for 3d printers

ABSTRACT

This disclosure relates in general to three dimensional (“3D”) printers having a configuration that prepares a three-dimensional object by using a feedstock comprising carbon containing photocurable formulations and methods for the preparation of such feedstocks. This disclosure further relates to electrically conducting 3D polymer composites prepared by using such carbon containing photocurable formulations.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 15/515,955filed Mar. 30, 2017 and entitled “3D PRINTERS AND FEEDSTOCKS FOR 3DPRINTERS” which is a United States national phase application under 35U.S.C. 371 of International Application No. PCT/US2015/052530, entitled“3D Printers and Feedstocks for 3D Printers,” filed on Sep. 27, 2015,which is based upon and claims priority to the U.S. provisional patentapplication No. 62/059,947, entitled “Nanocarbon Composites for 3DPrinting,” filed Oct. 5, 2014, and to the U.S. provisional patentapplication No. 62/184,867, entitled “Nanocarbon Composites for 3DPrinting,” filed Jun. 26, 2015.

BACKGROUND Technical Field

This disclosure relates in general to three dimensional (“3D”) printershaving a configuration that prepares a three-dimensional object by usinga feedstock comprising a carbon containing photocurable polymer or resinformulation or compound. This disclosure also relates to such feedstocksand their preparation methods. This disclosure further relates to 3Dcomposite objects prepared by using such printers and feedstocks. Thisdisclosure also relates to carbon containing photocurable formulationsand methods for their preparation. This disclosure further relates toelectrically conducting 3D polymer composites prepared by using suchcarbon containing photocurable formulations. This disclosure furtherrelates to 3D objects prepared by using such printers and feedstocks.

Description of Related Art

3D printing, also known as additive manufacturing, is a technology ofbuilding three dimensional (3D) solid objects by depositing layers ofmaterials in a design defined by a computer software using many of thecommonly available CAD (computer aided design) packages. This technologycan create highly customized complex parts and products that aredifficult or impossible to manufacture using traditional technologies.

There are several major 3D printing technologies differing mainly in theway layers are built to create the final 3D object. Some methods usemelting or softening materials to produce the layers. The second groupof methods, exemplified by Fused Deposition Modeling (FDM), works byextruding melted plastic filaments through an extrusion nozzle. Thethird group of methods such as stereolithography (SLA) and Digital LightProcessing (DLP) are based on curing (solidifying) liquid materials(such as photopolymer resins) with electromagnetic radiation in UV,visible, or IR ranges. Typically, SLA lasers require much less powercompared to SLS lasers. For example, the popular Form1+3D printermanufactured by Formlabs (Somerville, Mass.) uses a 0.12 watt laseroperating at about 405 nanometer wavelength.

Current challenges include improving the available 3D printing materialsto impart advanced properties and versatility needed for industrialapplications, as well as enabling faster 3D printing processes.

For further disclosures related to the nanocarbon 3D printing materials(including nanocarbon oxides), for example, see the followingpublications: M. N. dos Santos, C. V. Opelt, S. H. Pezzin, C. A. C. E.da Costa, J. C. Milan, F. H. Lafratta, and L. A. F. Coelho,Nanocomposite of photocurable epoxy-acrylate resin and carbon nanotubes:dynamic-mechanical, thermal and tribological properties, MaterialsResearch, 16 (2), 367-374 (2013); M. Sangermano, E. Borella, A. Priola,M. Messori, R. Taurino, and P. Potschke, Use of single-walled carbonnanotubes as reinforcing fillers in UV-curable epoxy systems.Macromolecular Materials and Engineering, 293(8), 708-713 (2008); Y. F.Zhu, C. Ma, W. Zhang, R. P. Zhang, N. Koratkar, and J. Liang, Alignmentof multiwalled carbon nanotubes in bulk epoxy composites via electricfield. Journal of Applied Physics, 105(5), 1-6 (2009); M.Martin-Gallego, M. Hernandez, V. Lorenzo, R. Verdejo, M. A.Lopez-Manchado, and M. Sangermano, Cationic photocured epoxynanocomposites filled with different carbon fillers. Polymer, 53(9),1831-1838 (2012); M. N. dos Santos, C. V. Opelt, F. H. Lafratta,Lepienski C M, S. H. Pezzin, and L. A. F. Coelho, Thermal and mechanicalproperties of a nanocomposite of a photocurable epoxy-acrylate resin andmultiwalled carbon nanotubes, Materials Science and Engineering A:Structural Materials Properties Microstructure and Processing,528(13-14), 4318-4324 (2011); F. H. Gojny, M. H. G. Wichmann, U. Kopke,B. Fiedler, and K. Schulte, Carbon nanotube-reinforced epoxy-composites: enhanced stiffness and fracture toughness at low nanotubecontent, Composites Science and Technology, 64(15), 2363-2371 (2004); B.Dong, Z. Yang, Y. Huang, and H. L. Li, Study on tribological propertiesof multi-walled carbon nanotubes/epoxy resin nanocomposites, TribologyLetters, 20(3-4), 251-254 (2005); S. Ushiba, S. Shoji, K. Masui, P.Kuray, J. Kono, and S. Kawata, 3D microfabrication of single-wall carbonnanotube/polymer composites by two-photon polymerization lithography,Carbon 59, 283-288 (2013). The entire content of each of thesepublications is incorporated herein by reference.

A variety of CNT materials (i.e., single-wall, double-wall, andmulti-wall CNTs) are commercially available as dry powders and/orsuspensions. These CNT materials may be synthesized by variety of CNTsynthesis methods. Some examples of the CNT synthesis methods arearc-discharge methods, laser-vaporization methods, and chemical vapordeposition method (CVD). See, for example, following publications: M.Kumar and Y. Ando, Chemical Vapor Deposition of Carbon Nanotubes: AReview on Growth Mechanism and Mass Production, Journal of Nanoscienceand Nanotechnology, vol. 10, pp. 3739-3758 (2010); G. L. Hornyak, L.Grigorian, A. C. Dillon, P. A. Parilla, K. M. Jones, and M. J. Heben, ATemperature Window for Chemical Vapor Decomposition Growth ofSingle-Wall Carbon Nanotubes, Journal of Physical Chemistry B, vol. 106,pp. 2821-2825 (2002); L. Grigorian, G. L. Hornyak, A. C. Dillon, and M.J. Heben, Continuous growth of single-wall carbon nanotubes usingchemical vapor deposition, U.S. Pat. No. 7,431,965, Oct. 7, 2008. Theentire content of each of these publications is incorporated herein byreference.

The arc-discharge method employs evaporation of metal-catalyzed graphiteelectrodes in electric arcs that involve very high (about 4,000° C.)temperatures. The laser-vaporization method employs evaporation ofgraphite target by lasers in conjunction with high-temperature furnaces.These two methods operate in a batch mode and may therefore be poorlysuited to high-volume, low cost production. The CVD method is based ondecomposition of carbon-containing gases on supported catalyst and mayoffer the more efficient, low-cost, and scalable method of producingCNTs. Currently, most commercial CNT materials are manufactured by theCVD method.

For examples of 3D printers and 3D printing techniques, see: Sachs etal. “Three-Dimensional Printing Techniques” U.S. Pat. No. 5,204,055; andKramer et al. “Systems and Methods for Using Multi-Part CurableMaterials” U.S. Patent Application Publication No. 2005/0012247. Theentire content of each of these patents and patent applications isincorporated herein by reference.

SUMMARY OF THE INVENTION

This disclosure relates in general to three dimensional (“3D”) printershaving a configuration that prepares three-dimensional objects by usinga feedstock comprising a carbon containing photocurable polymerformulation or compound. This disclosure also relates to such feedstocksand their preparation methods. This disclosure further relates to 3Dcomposite objects prepared by using such printers and feedstocks. Thisdisclosure also relates to carbon containing photocurable formulationsand methods for their preparation. This disclosure further relates toelectrically conducting 3D polymer composites prepared by using suchcarbon containing photocurable formulations.

This disclosure also relates to carbon containing photocurableformulations and methods for their preparation and to electricallyconducting 3D polymer composites prepared by using such carboncontaining photocurable formulations. Addition of carbons tophotocurable formulations may impart high electrically conductivity andalso improve mechanical, thermal, and other properties of 3D-printedpolymer objects. For example, carbon containing polymer composites mayhave higher tensile strength and be less flammable compared to pristinepolymer objects.

The instant disclosure also relates to a carbon containing photocurableformulation. This formulation may comprise a carbon; a photocurableresin; and a photoinitiator (i.e. photo-catalyst). The carbon containingphotocurable formulation, when cured, may yield a polymer composite withan electrical resistivity lower than or equivalent to 100 ohmcm, orlower than or equivalent to 10 ohmcm, or lower than or equivalent to 1ohmcm, or lower than or equivalent to 0.1 ohmcm.

The carbon containing photocurable formulation may comprise ananocarbon, a pyrolytic carbon, a graphite, an activated carbon, anamorphous carbon, a carbon fiber, or a combination thereof. The carbonmay comprise a nanocarbon. The carbon may comprise a non-agglomeratednanocarbon. The nanocarbon may comprise a carbon nanotube, a graphene, afullerene, or a combination thereof. The carbon nanotube may comprise asingle-wall carbon nanotube, a double-wall carbon nanotube, a multi-wallcarbon nanotube, or a combination thereof. The graphene may comprise asingle layer graphene, a double layer graphene, a multilayer graphene, agraphene strip, or a combination thereof. The fullerene may comprise aC₆₀, a C₇₀, a C₇₆, a C₇₈, a C₈₄, or a combination thereof.

The photocurable resin may comprise a photocurable monomer, aphotocurable oligomer, a photocurable polymer, or a combination thereof.The photocurable resin may comprise a monomer, oligomer, or a polymer ofa hydrocarbon. The hydrocarbon may be any hydrocarbon. For example, thehydrocarbon may be an acrylate, a methacrylate, an epoxy, a urethane, anester, a silicone, a styrene, or a combination thereof. For example, thehydrocarbon may comprise a monofunctional hydrocarbon, a difunctionalhydrocarbon, a trifunctional hydrocarbon, a multifunctional hydrocarbon,or a combination thereof.

The carbon containing photocurable formulation may have a viscosity. Theviscosity of the carbon containing photocurable formulation is in therange of 1 millipascalsecond to 1,000 millipascalsecond at about 25° C.;or in the range of 10 millipascalsecond to 300 millipascalsecond atabout 25° C.; or in the range of 50 millipascalsecond to 150millipascalsecond at about 25° C.

The carbon containing photocurable formulation may comprise a carbonnanotube. The carbon nanotube may comprise a single-wall carbonnanotube, a double-wall carbon nanotube, a multi-wall carbon nanotube,or a combination thereof. The carbon containing photocurableformulation, when cured, may yield a polymer composite with anelectrical resistivity lower than or equivalent to 1 ohmcm.

Any three-dimensional polymer composite object prepared by using any ofthe carbon containing photocurable formulations disclosed above iswithin the scope of the instant disclosure.

The instant disclosure also relates to a method of preparation of acarbon containing photocurable formulation. The method may compriseprocessing a conditioned photocurable mixture at a high shear rate andthereby preparing a carbon containing photocurable formulation. Theconditioned photocurable mixture may be prepared by a method comprisingprocessing a photocurable mixture at a low shear rate. The photocurablemixture may comprise a carbon, a photocurable resin, and aphotoinitiator. The high shear rate may be equivalent to or higher than200,000 s⁻¹; or equivalent to or higher than 500,000 s⁻¹; or equivalentto or higher than 1,000,000 s⁻¹; or equivalent to or higher than10,000,000 s⁻¹. The low shear rate may be lower than 200,000 s⁻¹.

The conditioned photocurable mixture may be substantially free of anydispersing agent. The photocurable mixture may be substantially free ofany dispersing agent.

The carbon may substantially be free of functional groups that canfacilitate dispersion of the carbon compound in the mixture.

The carbon may comprise a nanocarbon, a pyrolytic carbon, a graphite, anactivated carbon, an amorphous carbon, a carbon fiber, or a combinationthereof. The nanocarbon may comprise a carbon nanotube, a graphene, afullerene, or a combination thereof. The carbon nanotube may comprise asingle-wall carbon nanotube, a double-wall carbon nanotube, a multi-wallcarbon nanotube, or a combination thereof. The graphene may comprise asingle layer graphene, a double layer graphene, a multilayer graphene, agraphene strip, or a combination thereof. The fullerene may comprise aC₆₀, a C₇₀, a C₇₆, a C₇₈, a C₈₄, or a combination thereof.

The photocurable resin may comprise a photocurable monomer, aphotocurable oligomer, a photocurable polymer, or a combination thereof.

The photocurable resin may comprise a monomer, oligomer or a polymer ofan acrylate, a methacrylate, an epoxy, a urethane, an ester, a silicone,a vinyl alcohol, a vinyl acetate, an alkene, a glycerol, a glycol, aketone, or a combination thereof.

The carbon containing photocurable formulation has a viscosity, whereinthe viscosity of the carbon containing photocurable formulation may inthe range of 1 millipascalsecond to 1,000 millipascalsecond at about 25°C.; or in the range of 10 millipascalsecond to 300 millipascalsecond atabout 25° C.; or in the range of 50 millipascalsecond to 150millipascalsecond at about 25° C.

The carbon containing photocurable formulation, when cured, may yield apolymer composite with an electrical resistivity lower than orequivalent to 100 ohmcm; or lower than or equivalent to 10 ohmcm; orlower than or equivalent to 1 ohmcm; or lower than or equivalent to 0.1ohmcm.

In this preparation method the carbon may comprise a carbon nanotube.The carbon nanotube may comprise a single-wall carbon nanotube, adouble-wall carbon nanotube, a multi-wall carbon nanotube, or acombination thereof. The carbon containing photocurable formulation,when cured, may yield a polymer composite with an electrical resistivitylower than or equivalent to 1 ohmcm.

Any three-dimensional polymer composite object prepared by using any ofthe carbon containing photocurable formulation disclosed above, whichmay be prepared by any of the methods suitable for preparation of suchformulations may be within the scope of the instant disclosure.

Any combination of the above feedstocks; methods of preparation of suchfeedstocks; carbon containing photocurable formulations; methods ofpreparation of such formulations; 3D printers; 3D printers that use suchfeedstocks and/or such formulations; 3D objects; methods of preparationof such 3D objects by using such 3D printers, feedstocks andformulations may be within the scope of the instant disclosure.

These, as well as other components, steps, features, objects, benefits,and advantages, will now become clear from a review of the followingdetailed description of illustrative embodiments, the accompanyingdrawings, and the exemplary features.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings are of illustrative embodiments. They do not illustrate allembodiments. Other embodiments may be used in addition or instead.Details that may be apparent or unnecessary may be omitted to save spaceor for more effective illustration. Some embodiments may be practicedwith additional components or steps and/or without all of the componentsor steps that are illustrated. When the same numeral appears indifferent drawings, it refers to the same or like components or steps.

FIG. 1. An exemplary SEM (scanning electron microscope) image of a driedCNT mat showing agglomerated and tangled CNT bundles. The scale bar atthe left bottom corner (shown in white color) equals about 1 micrometer.

FIG. 2. Examples of 3D-printed polymer composite objects: (A) CNT-basedcomposite object of Example 4, (B) C₆₀-based composite object of Example5, and (C) reference polymer object (with no carbon) of Example 6.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

Illustrative embodiments are now described. Other embodiments may beused in addition or instead. Details that may be apparent or unnecessarymay be omitted to save space or for a more effective presentation. Someembodiments may be practiced with additional components or steps and/orwithout all of the components or steps that are described.

In this disclosure, the word “form” may mean “deposit”, “coat”,“dispose”, “laminate”, “apply”, “place”, “provide”, “position”,“manufacture” or the like. In this disclosure, the phrase “anycombination thereof” or “a combination thereof” may mean “a mixturethereof”, “a composite thereof”, “an alloy thereof”, or the like. Inthis disclosure, the indefinite article “a” and phrases “one or more”and “at least one” are synonymous and mean “at least one”.

This disclosure relates to carbon containing photocurable formulationsand methods for their preparation. This disclosure further relates toelectrically conducting 3D polymer composites prepared by using suchcarbon containing photocurable formulations. This disclosure furtherrelates to 3D composite objects prepared by using three-dimensional(“3D”) printers and such feedstocks.

Addition of carbons and, in particular, nanocarbons, such as carbonnanotubes (CNT), graphenes (GR), fullerenes (FL), and their mixtures invarious proportions and combinations, to plastic or polymers may lead toformation of nanocarbon composites with increased electricalconductivity, increased thermal conductivity, increased mechanicalstrength, and other improvements in properties.

Addition of nanocarbons also may lead to increased absorption ofincident light in wide frequency range (e.g., UV, visible, IR) therebyimproving the efficiency of irradiative heating of the feedstock andphotochemical reactions. This may lead to higher rates and increasedthroughput of applicable 3D printing processes, thereby making 3Dprinted polymer or photo-curable resin parts more competitive on themarket.

A major challenge in these tasks is ensuring high degree of dispersionof carbon in the polymer or photo-curable resin since onlywell-dispersed carbons impart useful properties. Typically, carbonagglomeration results in underutilized potential of the compositematerial and degraded properties of polymer or photo-curable resinproduct.

Another challenge is preventing structural or other damage to carbons inthe process of fabrication of polymer or photo-curable resin nanocarboncomposites. Damaged carbons may exhibit inferior properties whenincorporated in composite materials.

The polymer or photo-curable feedstocks of the instant disclosure mayprovide several advantages to the 3D printing of objects. For example,three dimensional objects may be printed at higher throughputs by usingthe polymer or photo-curable feedstocks of the instant disclosure. Theproduction costs of such polymer or photo-curable resin article maythereby be decreased while production rates are increased. The use ofthese polymer or photo-curable feedstocks may also decrease the powerrequirements of the 3D printers, thereby decreasing the prices of suchprinters.

The polymer or photo-curable feedstocks of the instant disclosure mayalso provide polymer or photo-curable materials with improved propertiesfor 3D printing technologies. These improvements may include (but notlimited to) higher electrical and thermal conductivity, bettermechanical and thermal properties.

The instant disclosure also relates to a carbon containing photocurableformulation. This formulation may comprise a carbon; a photocurableresin; and a photoinitiator (i.e. photo-catalyst). The carbon containingphotocurable formulation, when cured, may yield a polymer composite withan electrical resistivity lower than or equivalent to 100 ohmcm, orlower than or equivalent to 10 ohmcm, or lower than or equivalent to 1ohmcm, or lower than or equivalent to 0.1 ohmcm.

The carbon containing photocurable formulation may comprise ananocarbon, a pyrolytic carbon, a graphite, an activated carbon, anamorphous carbon, a carbon fiber, or a combination thereof. The carbonmay comprise a nanocarbon. The carbon may comprise a non-agglomeratednanocarbon. The nanocarbon may comprise a carbon nanotube, a graphene, afullerene, or a combination thereof. The carbon nanotube may comprise asingle-wall carbon nanotube, a double-wall carbon nanotube, a multi-wallcarbon nanotube, or a combination thereof. The graphene may comprise asingle layer graphene, a double layer graphene, a multilayer graphene, agraphene strip, or a combination thereof. The fullerene may comprise aC₆₀, a C₇₀, a C₇₆, a C₇₈, a C₈₄, or a combination thereof.

The photocurable resin may comprise a photocurable monomer, aphotocurable oligomer, a photocurable polymer, or a combination thereof.The photocurable resin may comprise a monomer, oligomer, or a polymer ofa hydrocarbon. The hydrocarbon may be any hydrocarbon. For example, thehydrocarbon may be an acrylate, a methacrylate, an epoxy, a urethane, anester, a silicone, a styrene, or a combination thereof. For example, thehydrocarbon may comprise a monofunctional hydrocarbon, a difunctionalhydrocarbon, a trifunctional hydrocarbon, a multifunctional hydrocarbon,or a combination thereof.

The carbon containing photocurable formulation has a viscosity. Theviscosity of the carbon containing photocurable formulation is in therange of 1 millipascalsecond to 1,000 millipascalsecond at about 25° C.;or in the range of 10 millipascalsecond to 300 millipascalsecond atabout 25° C.; or in the range of 50 millipascalsecond to 150millipascalsecond at about 25° C.

The carbon containing photocurable formulation may comprise a carbonnanotube, and wherein the carbon nanotube may comprise a single-wallcarbon nanotube, a double-wall carbon nanotube, a multi-wall carbonnanotube, or a combination thereof; wherein the carbon containingphotocurable formulation, when cured, may yield a polymer composite withan electrical resistivity lower than or equivalent to 1 ohmcm.

Any three-dimensional polymer composite object prepared by using any ofthe carbon containing photocurable formulations disclosed above iswithin the scope of the instant disclosure.

The instant disclosure also relates to a method of preparation of acarbon containing photocurable formulation. The method may compriseprocessing a conditioned photocurable mixture at a high shear rate andthereby preparing a carbon containing photocurable formulation. Theconditioned photocurable mixture may be prepared by a method comprisingprocessing a photocurable mixture at a low shear rate. The photocurablemixture may comprise a carbon, a photocurable resin, and aphotoinitiator. The high shear rate may be equivalent to or higher than200,000 s⁻¹; or equivalent to or higher than 500,000 s⁻¹; or equivalentto or higher than 1,000,000 s⁻¹; or equivalent to or higher than10,000,000 s⁻¹. The low shear rate may be lower than 200,000 s⁻¹.

The conditioned photocurable mixture may substantially be free of anydispersing agent. The photocurable mixture may be substantially free ofany dispersing agent.

The carbon may substantially be free of functional groups that canfacilitate dispersion of the carbon compound in the mixture.

The carbon may comprise a nanocarbon, a pyrolytic carbon, a graphite, anactivated carbon, an amorphous carbon, a carbon fiber, or a combinationthereof. The nanocarbon may comprise a carbon nanotube, a graphene, afullerene, or a combination thereof. The carbon nanotube may comprise asingle-wall carbon nanotube, a double-wall carbon nanotube, a multi-wallcarbon nanotube, or a combination thereof. The graphene may comprise asingle layer graphene, a double layer graphene, a multilayer graphene, agraphene strip, or a combination thereof. The fullerene may comprise aC₆₀, a C₇₀, a C₇₆, a C₇₈, a C₈₄, or a combination thereof.

The photocurable resin may comprise a monomer, oligomer or a polymer ofan acrylate, a methacrylate, an epoxy, a urethane, an ester, a silicone,a vinyl alcohol, a vinyl acetate, an alkene, a glycerol, a glycol, aketone, or a combination thereof.

The carbon containing photocurable formulation has a viscosity, whereinthe viscosity of the carbon containing photocurable formulation may inthe range of 1 millipascalsecond to 1,000 millipascalsecond at about 25°C.; or in the range of 10 millipascalsecond to 300 millipascalsecond atabout 25° C.; or in the range of 50 millipascalsecond to 150millipascalsecond at about 25° C.

The carbon containing photocurable formulation, when cured, may yield apolymer composite with an electrical resistivity lower than orequivalent to 100 ohmcm; or lower than or equivalent to 10 ohmcm; orlower than or equivalent to 1 ohmcm; or lower than or equivalent to 0.1ohmcm.

In this preparation method the carbon may comprise a carbon nanotube.The carbon nanotube may comprise a single-wall carbon nanotube, adouble-wall carbon nanotube, a multi-wall carbon nanotube, or acombination thereof. The carbon containing photocurable formulation,when cured, may yield a polymer composite with an electrical resistivitylower than or equivalent to 1 ohmcm.

Any three-dimensional polymer composite object prepared by using any ofthe carbon containing photocurable formulation disclosed above, whichmay be prepared by any of the methods suitable for preparation of suchformulations may be within the scope of the instant disclosure.

As disclosed above, the CNT materials may be synthesized by variety ofCNT synthesis methods. The CNT formation and growth may stop during thesynthesis. The CNT formation and growth may stop due to decreasedcatalyst activity when the catalyst's surface is covered with anamorphous carbon layer. Or, the CNT formation and growth may be stoppedafter a pre-determined period of synthesis. At this process stage, theCNTs are “as-synthesized CNTs”.

The as-synthesized CNTs may be processed before they are used. Forexample, the as-synthesized CNTs may be incorporated into a liquid ormixed with a liquid. This incorporation may be done, for example, todissolve impurities (e.g. non-CNT material), to provide a CNTsuspension, or a combination thereof. Examples of impurities may benon-CNT carbons (e.g., amorphous carbon), inorganic catalysts, catalystsupports, or a combination thereof.

The liquid mixture at this process stage may comprise a liquid and anas-synthesized nanocarbon (“the nanocarbon slurry”). The liquid maycomprise any liquid. For example, the liquid may comprise water, ormixtures thereof. The solvent may comprise any solvent. For example, thesolvent may comprise a hydrocarbon solvent such as alcohol, ketone,ester, ether, alkane, alkene, aromatic hydrocarbons (such as benzene andvarious derivatives), or mixtures thereof. The nanocarbon slurry mayfurther comprise an acid, a base, a suspension agent, or a combinationthereof.

In one example, the CVD process may involve passing a hydrocarbon vaporthrough a reactor at a sufficiently high temperature, varying in therange of 600° C. to 1200° C., and in presence of a catalyst to decomposethe hydrocarbon. In one example, the catalyst may comprise metals and/ormetal oxides (e.g., Fe, Co, Ni, Mo, their oxides, and a combinationthereof). The catalyst may be nanoparticles of such metals and/or metaloxides. In one example, support material may comprise alumina, silica,magnesium oxide, and a combination thereof. The CNTs may form and growon catalyst particles in the reactor and may be collected upon coolingthe system to a room temperature. These CNTs collected directly from thereactor and not yet treated in any way are the as-synthesized CNTs. Theas-synthesized CNTs may comprise at least 50 wt % inorganic impuritiesincluding the catalyst and the support material, which may need to beremoved to produce a material comprising CNTs with desired properties.

In one example, the as-synthesized CNTs may be purified by beingimmersed in acids (such as H₂SO₄, HNO₃, HCl, and a combination thereof)and refluxed for a period varying in the range of 1 hour to 24 hoursresulting in significantly decreased amount of impurities (down to a fewwt % of impurities). The purified CNT material may be thoroughly washedto remove any residual acid and then dried in a convection oven at atemperature varying in the range of 20° C. to 150° C. for a periodvarying in the range of 1 hour to 48 hours.

The as-synthesized and purified CNTs may easily be dispersed in theliquid since they may not be substantially agglomerated. However, uponbeing wetted and subsequently dried, the CNT material may be convertedinto an agglomerated and tangled mat comprising irregular clusters ofindividual CNTs, as shown in FIG. 1. This post-drying transition mayoccur due to high amount of the CNTs' atomically smooth surface andattendant large surface energy. This condition may make the conformationof straight individual CNTs energetically unstable and susceptible todeformation and agglomeration.

The instability may greatly be enhanced by introducing a liquid betweenindividual CNTs and then evaporating the liquid. In other words, wettingand then drying CNTs may induce severe agglomeration due to attractionforces exerted by liquids in intimate contact with the CNT surface. Upondrying, CNTs may coalesce into large bundles (including tens to hundredsof CNTs in cross section), which then form a highly tangled structure,as shown in FIG. 1 by way of example. These agglomerated structures maynot exhibit many of the remarkable properties expected of individual,well-dispersed and/or isolated CNTs.

Commercially available CNT materials are typically those of the purifiedand dried grade, marketed either as a powder obtained after drying, oras a CNT suspension produced by re-dispersing the dry purified powder ineither an aqueous or organic solvent. The commercially availablepurified grades of the CNT materials (“the commercial CNTs”) may undergoat least one wetting and drying cycle before they are supplied to auser. The commercial CNTs may thereby have agglomerated structures.

It may then be difficult to disperse this agglomerated structure down tothe level of individual CNTs that may be required for many applications.To accomplish this task, commercially available grades of CNT materialsmay have to be subjected to vigorous harsh treatments that may consume alot of energy and inflict considerable collateral damage upon the CNTmaterial (e.g., by destroying some CNTs, creating defects in CNT walls,and/or cutting CNTs into shorter segments) resulting in degradednanocarbon material properties.

In one example, this disclosure relates to a method comprising using theas-synthesized CNTs, the non-agglomerated and/or non-damaged CNTs, theCNT slurry, or the combination thereof in preparation of the nanocarboncomposites. The drying-induced agglomeration and entanglement, as wellas damage during processing of agglomerated CNT may thereby be avoided.For example, the purified CNTs may be kept in a suspension or, at least,as the nanocarbon slurry (the “purified CNT slurry”). In other words,the as-synthesized CNT materials may be purified by refluxing in acidsbut then never be allowed to dry before reaching the customer, insteadbeing kept as the purified CNT slurry. The customer may either use thepurified CNT slurry or, if necessary, exchange the liquid with anotherliquid and process the CNT slurry as desired, allowing it to dry only atthe final step of their process. This arrangement would significantlyfacilitate dispersion and prevent damaging of CNT materials resulting inimprovement of product properties and performance.

The process of dispersing the purified CNT slurry material down to thelevel of individual CNTs may be accomplished through any of mixing,sonicating, or homogenizing techniques, or a combination thereof. Ascompared to the current commercial CNT materials, the dispersion of thepurified CNT slurry material may require much less effort and inflictmuch less damage to CNTs in the process of achieving the desired degreeof dispersion. The same considerations may apply to other types ofnanocarbon materials. Higher degree of dispersion and reduced damage tonanocarbon structure may result in improved properties. The dispersionprocess may be carried out in either aqueous or organic solvents.Examples of aqueous or organic solvents may comprise water, toluene,alcohol, carbon disulfide, dichlorobenzene, other benzene derivatives,aromatic solvents, dimethylformamide, N-methylpyrrolidinone, pyridine,and mixtures thereof.

The purified CNT slurry may comprise a liquid and a CNT. The CNT maycomprise less than 80 wt %, less than 50 wt %, or less than 10 wt % ofthe CNT slurry. Presence of sufficient number of liquid molecules inintimate contact with CNTs stabilizes the system and prevents CNTagglomeration.

A convenient method to evaluate the degree of agglomeration of CNTsincorporated into composite materials may be through examination ofscanning electron microscopy (SEM) and/or transmission electronmicroscopy (TEM) images. The CNT agglomerates are readily visible in SEMand/or TEM images at magnifications 1,000 or 30,000 times and less,depending on agglomerate size. The non-agglomerated CNTs are muchsmaller in size and may be seen in SEM and/or TEM images atmagnifications 40,000 or 80,000 times and higher.

The damage to CNTs caused by a harsh dispersion process may be evaluatedby measuring Raman spectroscopy, in particular, using the intensityratio of the so-called G-band and D-band. The G-bands that are typicallydetected at about 1,580 cm⁻¹ (within ±20 cm⁻¹) are due to thenon-defective graphitic CNT structure of, while the D-bands (at about1,350 cm⁻¹ within ±20 cm⁻¹) are predominantly due to structural defects,as disclosed by M. S. Dresselhaus, A. Jorio, A. G. Souza Filho and R.Saito, Defect characterization in graphene and carbon nanotubes usingRaman spectroscopy, Phil. Trans. Royal Society A, vol. 368, pp.5355-5377 (2010). The content of this publication is incorporated hereinby reference.

The intensity ratio of the G-band to the D-band (i.e., the G/D ratio)may be used as a measure of relative concentration of CNT defects.Similar evaluation process based on G/D ratio maybe used for graphenematerials, as disclosed by A. C. Ferrari, Raman spectroscopy of grapheneand graphite: Disorder, electron-phonon coupling, doping andnonadiabatic effects, Solid State Communications, vol. 143, pp. 47-57(2007). The content of this publication is incorporated herein byreference.

To evaluate the damage inflicted on CNT wall structure in the process ofdispersing the CNT material, the G/D ratio may be measured and comparedbefore and after the dispersion process. The comparison may be doneusing the same measurement conditions. The as-synthesized and/or thepurified CNT slurry may have the same or higher G/D ratio after thedispersion, while the agglomerated CNTs (e.g., dry powder) may havedecreased G/D ratio after the dispersion due to the damage inflicted onCNT material during the dispersion process. The G/D ratio of ananocarbon incorporated in a nanocarbon composite being 80% lower than,50% lower than, 25% lower than, 10% lower than that of theas-synthesized nanocarbon may indicate a non-damaged nanocarbon. Also,the G/D ratio of a nanocarbon incorporated in a composite being at least80% higher than, at least 50% higher than, at least 25% higher than, atleast 10% higher than, or at least equal to that of the as-synthesizednanocarbon may indicate a non-damaged nanocarbon.

The disclosure is illustrated further by the following additionalexamples that are not to be construed as limiting the disclosure inscope to the specific procedures or products described in them.

Example 1

As-synthesized multi-wall CNT material (comprising about 85 wt %inorganic impurities) was refluxed in excess amount of about 1M HCl forabout 5 hours, and then filtered to remove the main volume of the acidwhile keeping the CNT material wet. The purified product (comprisingabout 2 wt % inorganic impurities) was washed two times with de-ionizedwater to remove the residual acid, and then separated into three partsfor the experiments described in other Examples. The first part wasdried in a convection oven at about 120° C. for about 4 hours. Thesecond part was kept wet and refluxed in water (at CNT concentration ofabout 2 g/L) for about 5 hours to loosen up the CNTs. The third part waswashed with copious amounts of toluene three times thereby substantiallyreplacing the water with toluene as a solvent and bringing the CNTconcentration to about 2 g/L. Then, the CNT-toluene suspension wasrefluxed for about 5 hours. Finally, both these CNT suspensions (one inwater and one in toluene) were separately passed 2 times through aMicrofluidizer high shear fluid processor (LM-10, MicrofluidicsCorporation, Newton, Mass.) at 20,000 psi pressure yielding twosuspensions of non-agglomerated and/or non-damaged CNTs. Thesesuspensions were stable over the period of 4 weeks. The G/D ratio asmeasured with about 532 nm laser excitation varied in the range of 1.2to 1.6, both before and after dispersion indicating that theconcentration of structural defects did not change. All the abovetreatment steps are scalable and highly reproducible.

Example 2

Dried powder of purified multi-wall CNT material prepared in Example 1as the first part was dispersed following exactly the same process asthe other two parts. To produce a stable CNT suspension, the dry powderwas first refluxed in water at CNT concentration of about 2 g/L forabout 5 hours, then passed 2 times through the Microfluidizer. The G/Dratio for the multi-wall CNT dry powder material as measured with about532 nm laser excitation may vary in the range of 1.1 to 1.4. Afterdispersing, the G/D ratio decreased to a level varying in the range of0.4 to 0.8 indicating increased concentration of CNT defects.

The multi-wall CNT material may be provided, for example, by Thomas Swan& Co Ltd (UK), Nanocyl (Belgium), or many other suppliers. The step ofMicrofluidizer treatment may be combined or substituted with any highshear mixing, sonication, wet ball milling, another similar treatment,or a combination thereof. Similar simple and efficient process may bedesigned to produce the as-synthesized or the purified non-agglomeratedand/or non-damaged CNT slurries.

A highly dispersed and stable suspension of non-agglomerated and/ornon-damaged CNT material (“the well-dispersed CNT suspension”) in eitherwater or organic solvents is thereby obtained. The well-dispersed CNTsuspension may be used in preparation of composites suitable for the 3Dprinting.

Example 3

A typical procedure to produce electrically conducting 3D-printablephotopolymer resin for use in SLA technology is described in thisexample.

The toluene suspension of non-agglomerated and/or non-damaged CNTprepared according to the process described in Example 1 may be added toa liquid acrylic resin in a desired proportion and agitated for about 5hours at about 50° C. with a magnetic stirrer to ensure uniformdistribution of CNT throughout the resin's volume. The liquid acrylicresin may be, in particular, MakerJuice SF resin, and the CNT suspensionmay be added at about 20 wt %. The CNT content in the resin should behigh enough to ensure desired electrical conductivity, but also lowenough to keep the viscosity below about 1,000 (millipascalsecond) atabout 25° C. otherwise the resin will be difficult to 3D print. Othercommercially available resins, different proportions of the CNTsuspension, and different solvents may also be used. For example,aromatic solvents with covalently attached photocurable functionalgroups, such as acrylic, metacrylic, and/or epoxy and theircombinations, may be used instead of toluene to disperse and suspend CNTand further serve as photocurable resin ingredients. Examples of suchphotocurable resin ingredients are benzyl 2-ethyl acrylate, benzylmethacrylate, pyridine acrylate, toluene acrylate, xylene acrylate, andthe like. The resin ingredients may comprise a single photocurablefunctional group (e.g., mono-acrylates), two photocurable functionalgroups (e.g., di-acrylates), multiple photocurable functional groups(e.g., tri-, tetra, and other poly-acrylates), and their combinations.The resulting CNT-containing resin is then loaded into an SLA 3Dprinter. Under a UV or visible light irradiation, the acrylic resinsolidifies through a photopolymerization reaction forming the desired3D-printed plastic object defined by a computer system configured forthis purpose. In the photopolymerization process, the suspendednon-agglomerated and/or non-damaged CNTs are captured within the newlyformed polymer structure imparting increased electrical and thermalconductivity, improved mechanical and thermal properties, as well asdecreased flammability.

Example 4

An alternative (to Example 3) approach to producing electricallyconducting 3D-printable photopolymer resin for use in SLA technology isdescribed in this example.

A 250 mg of as-received single-wall CNT (Thomas Swan, Elicarb® SWNT) wasadded to 90 mL of bisphenol-A [4 EO] diacrylate (IGM Resins, Photomer4062) and 30 mg of Nonyl phenol [4 EO] acrylate (IGM Resins, Photomer4003), mixed by stirring with magnetic stirrer bar at 1,000 rpm andabout 40° C. for 5 hours. Then, 80 mL of pentaerythritol [5 EO]tetraacrylate (IGM Resins, Photomer 4172), 50 mL polyethylene glycol(200) di-methacrylate (IGM Resins, Photomer 2050), and 250 mg2,4,6-trimethylbenzoyl-diphenyl phosphine oxide (IGM Resins, OmniradTPO) were added to the mixture and stirred for additional 5 hours atabout 1,000 rpm and about 40° C. In the finishing step, the mixture waspassed once through a Microfluidizer device (Microfluidics, LM-10) toensure good dispersion of CNT and other ingredients. The resulting resinwas loaded into Formlabs Form1+SLA 3D printer to produce electricallyconducting 3D-printed plastic objects of various shapes (FIG. 2(A)).Both the resin and the 3D-printed objects were of black color.Electrical resistivity was measured in 3D-printed objects shaped asrectangular strips (about 10 cm in length, about 2 cm in width, about0.2 cm in thickness) using a four-probe technique. The electricalresistivity at about 25° C. was about 1 Ohmcm on average with standarddeviation of about 15%.

Example 5

This example describes an electrically conducting 3D-printablephotopolymer resin suitable for use in SLA technology similar to Example4.

A 1,500 mg of as-received Fullerene-C₆₀ (Sigma Aldrich, 99.5%, #379646)was added to 120 mL of bisphenol-A [4 EO] diacrylate (IGM Resins,Photomer 4062), 80 mL of pentaerythritol [5 EO] tetraacrylate (IGMResins, Photomer 4172), 50 mL polyethylene glycol (200) di-methacrylate(IGM Resins, Photomer2050), and 500 mg 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (IGM Resins, Omnirad TPO). The mixture was stirred withmagnetic stirrer bar at 1,000 rpm for 20 hours and about 50° C. Then,the mixture was passed once through a Microfluidizer device(Microfluidics, LM-10) to ensure good dispersion of the ingredients. Theresulting resin was loaded into Formlabs Form1+SLA 3D printer to produceelectrically conducting 3D-printed plastic objects of various shapes(FIG. 2(B)). Both the resin and the 3D-printed objects were of browncolor. Electrical resistivity was measured in 3D-printed objects shapedas rectangular strips (about 10 cm in length, about 2 cm in width, about0.2 cm in thickness) using a four-probe technique. The electricalresistivity at about 25° C. was about 8 MegaOhmcm on average withstandard deviation of about 50%.

Example 6

This example describes fabrication of reference photopolymer resinsuitable for use in SLA technology similar to Examples 4 and 5. Thisresin does not contain any carbon additives and yields electricallyinsulating polymer objects.

A 120 mL of bisphenol-A [4 EO] diacrylate (IGM Resins, Photomer 4062),80 mL of pentaerythritol [5 EO] tetraacrylate (IGM Resins, Photomer4172), 50 mL polyethylene glycol (200) di-methacrylate (IGM Resins,Photomer2050), and 1,000 mg 2,4,6-trimethylbenzoyl-diphenyl phosphineoxide (IGM Resins, Omnirad TPO) were loaded together in a glass vial andstirred with magnetic stirrer bar at 1,000 rpm for 20 hours and about50° C. Then, the mixture was passed once through a Microfluidizer device(Microfluidics, LM-10) to ensure good dispersion of the ingredients. Theresulting carbon additive-free photocurable resin formulation was loadedinto Form labs Form1+SLA 3D printer to produce reference 3D-printedplastic objects of various shapes (FIG. 2(C)). Both the resin and the3D-printed objects were of weakly yellow color. Electrical resistivitywas measured in 3D-printed objects shaped as rectangular strips (about10 cm in length, about 2 cm in width, about 0.2 cm in thickness) using afour-probe technique. The electrical resistivity at about 25° C. wasabove the measurement range of the instrument, that is, >200 MegaOhmscmindicating that the sample was electrically insulating. Note that inthis Example a much higher concentration of the photoinitiator (i.e.,2,4,6-trimethylbenzoyl-diphenyl phosphine oxide) had to be used comparedto the carbon-containing resins of Examples 10 and 11. Similarphotocurable formulations can be prepared using a variety of other mono-and poly-functional acrlylates, methacrylates, epoxies, styrenes,urethanes, esters, silicones, acetates, glycols, ketones, and theircombinations. For example, multifunctional monomeric methacrylatesinclude ethylene glycol dimethacrylate, diethylene glycoldimethacrylate, triethylene glycol dimethacrylate, polyethylene glycoldimethacrylate, 2,2 bis[4-(methacryloxyethoxy)phenyl] propane,tricylodecane dimethanol dimethacrylate, 1,10-decandiol dimethacrylate,1,6-hexanediol dimethacyrlate, 1,9-nonanediol dimethacrylate, neopentylglycol dimethacrylate, 2-hydroxy 1-3 dimethacryloxy propane,trimethyolpropane trimethacrylate, ethoxylated trimethyol propanetrimethacrylate, ditrimethyolpropane tetramethacrylate, tris (2-hydroxyethyl) isocyanurate trimethacrylate, dipentaerythritolpentamethacrylate, ethyoxylated pentaerythritol tetramethacrylate,propoxylated glyceryl trimethacrylate, propoxylated trimethylolpropanetrimethacrylate, and polyester dendrimer.

Other type CNTs, graphenes and/or fullerenes may also be employed inthis application either alone or in various combinations. Graphene maybe present either as graphene oxide or pure graphene. The graphene oxidemay be expected to be reduced to pure graphene due to the UV radiationin the process of photopolymerization. Other photopolymer resins, suchas methacrylates, epoxies, urethanes, polyesters, silicones, and theircombinations and blends may also be used in this technique. All thosepolymers may be commercially available from many suppliers. Other mixingtechniques such as high shear mixing, sonication, wet ball milling, orother similar treatments and their combinations may also be applied asneeded.

Addition of nanocarbons to photopolymers may also impact the rate ofphotopolymerization reaction due to strong absorption of the UV andvisible range radiation by nanocarbons and very high values for freecharge carrier mobility. In nanocarbons, absorption the UV and visiblerange radiation may generate photo-excited electrons that may rapidly bere-distributed throughout the entire system. The overall impact may bebeneficial resulting in notable increase of the reaction rate due tohigh mobility and eventually leading to faster production times andhigher throughput, which is essential for commercial success of 3Dprinting technologies. Carbon-containing resins may also require lessphotoinitiator to start the reaction leading to cost savings sincephotoinitiators may be the most expensive ingredient in the photocurableresins.

In that regard, of special interest may be the fullerene photopolymercomposites since fullerenes may have a rich photochemistry and, inparticular, photopolymerization reactions of their own. Hence, presenceof fullerenes in nanocarbon composite materials may lead to the highestimprovement in the photopolymerization reaction rates.

Any combination of the above feedstocks; methods of preparation of suchfeedstocks; carbon containing photocurable formulations; methods ofpreparation of such formulations; 3D printers; 3D printers that use suchfeedstocks and/or such formulations; 3D objects; methods of preparationof such 3D objects by using such 3D printers, feedstocks andformulations may be within the scope of the instant disclosure.

In this specification and the appended claims, the singular forms “a,”“an” and “the” include plural referents unless the context clearlydictates otherwise.

The components, steps, features, objects, benefits, and advantages thathave been discussed are merely illustrative. None of them, nor thediscussions relating to them, are intended to limit the scope ofprotection in any way. Numerous other embodiments are also contemplated.These include embodiments that have fewer, additional, and/or differentcomponents, steps, features, objects, benefits, and/or advantages. Thesealso include embodiments in which the components and/or steps arearranged and/or ordered differently.

Unless otherwise stated, all measurements, values, ratings, positions,magnitudes, sizes, and other specifications that are set forth in thisspecification, including in the exemplary features that follow, areapproximate, not exact. They are intended to have a reasonable rangethat is consistent with the functions to which they relate and with whatis customary in the art to which they pertain.

All articles, patents, patent applications, and other publications thathave been cited in this disclosure are incorporated herein by reference.

The phrase “means for” when used in a feature is intended to and shouldbe interpreted to embrace the corresponding structures and materialsthat have been described and their equivalents. Similarly, the phrase“step for” when used in a feature is intended to and should beinterpreted to embrace the corresponding acts that have been describedand their equivalents. The absence of these phrases from a feature meansthat the feature is not intended to and should not be interpreted to belimited to these corresponding structures, materials, or acts, or totheir equivalents.

The scope of protection is limited solely by the claims that now follow.That scope is intended and should be interpreted to be as broad as isconsistent with the ordinary meaning of the language that is used in theclaims when interpreted in light of this specification and theprosecution history that follows, except where specific meanings havebeen set forth, and to encompass all structural and functionalequivalents.

Relational terms such as “first” and “second” and the like may be usedsolely to distinguish one entity or action from another, withoutnecessarily requiring or implying any actual relationship or orderbetween them. The terms “comprises,” “comprising,” and any othervariation thereof when used in connection with a list of elements in thespecification or claims are intended to indicate that the list is notexclusive and that other elements may be included. Similarly, an elementproceeded by an “a” or an “an” does not, without further constraints,preclude the existence of additional elements of the identical type.

None of the claims are intended to embrace subject matter that fails tosatisfy the requirement of Sections 101, 102, or 103 of the Patent Act,nor should they be interpreted in such a way. Any unintended coverage ofsuch subject matter is hereby disclaimed. Except as just stated in thisparagraph, nothing that has been stated or illustrated is intended orshould be interpreted to cause a dedication of any component, step,feature, object, benefit, advantage, or equivalent to the public,regardless of whether it is or is not recited in the claims.

The abstract is provided to help the reader quickly ascertain the natureof the technical disclosure. It is submitted with the understanding thatit will not be used to interpret or limit the scope or meaning of theclaims. In addition, various features in the foregoing detaileddescription are grouped together in various embodiments to streamlinethe disclosure. This method of disclosure should not be interpreted asrequiring claimed embodiments to require more features than areexpressly recited in each claim. Rather, as the following claimsreflect, inventive subject matter lies in less than all features of asingle disclosed embodiment. Thus, the following claims are herebyincorporated into the detailed description, with each claim standing onits own as separately claimed subject matter.

1. A carbon containing photocurable formulation comprising: a carbon; aphotocurable resin; and a photoinitiator; wherein the carbon containingphotocurable formulation, when cured, yields a polymer composite with anelectrical resistivity lower than or equivalent to 100 ohmcm.
 2. Thecarbon containing photocurable formulation of claim 1, wherein thecarbon containing photocurable formulation, when cured, yields a polymercomposite with an electrical resistivity lower than or equivalent to 10ohmcm.
 3. The carbon containing photocurable formulation of claim 1,wherein the carbon containing photocurable formulation, when cured,yields a polymer composite with an electrical resistivity lower than orequivalent to 1 ohmcm.
 4. The carbon containing photocurable formulationof claim 1, wherein the carbon containing photocurable formulation, whencured, yields a polymer composite with an electrical resistivity lowerthan or equivalent to 0.1 ohmcm.
 5. The carbon containing photocurableformulation of claim 1, wherein the carbon containing photocurableformulation comprises a nanocarbon, a pyrolytic carbon, a graphite, anactivated carbon, an amorphous carbon, a carbon fiber, or a combinationthereof.
 6. The carbon containing photocurable formulation of claim 1,wherein the carbon comprises a nanocarbon.
 7. The carbon containingphotocurable formulation of claim 1, wherein the carbon comprises anon-agglomerated nanocarbon.
 8. The carbon containing photocurableformulation of claim 1, wherein the carbon comprises a nanocarbon andwherein the nanocarbon comprises a carbon nanotube, a graphene, afullerene, or a combination thereof.
 9. The carbon containingphotocurable formulation of claim 1, wherein the carbon comprises acarbon nanotube; and wherein the carbon nanotube comprises a single-wallcarbon nanotube, a double-wall carbon nanotube, a multi-wall carbonnanotube, or a combination thereof.
 10. The carbon containingphotocurable formulation of claim 1, wherein the carbon comprises ananocarbon, and wherein the nanocarbon comprises a graphene; and whereinthe graphene comprises a single layer graphene, a double layer graphene,a multilayer graphene, a graphene strip, or a combination thereof. 11.The carbon containing photocurable formulation of claim 1, wherein thecarbon comprises a fullerene; and wherein the fullerene comprises a C₆₀,a C₇₀, a C₇₆, a C₇₈, a C₈₄, or a combination thereof.
 12. The carboncontaining photocurable formulation of claim 1, wherein the photocurableresin comprises a monomer, oligomer, or a polymer of an acrylate, amethacrylate, an epoxy, a urethane, an ester, a silicone, a styrene, ora combination thereof.
 13. The carbon containing photocurableformulation of claim 1, wherein the carbon containing photocurableformulation has a viscosity; and wherein the viscosity of the carboncontaining photocurable formulation is in the range of 1millipascalsecond to 1,000 millipascalsecond at about 25° C.
 14. Thecarbon containing photocurable formulation of claim 1, wherein thecarbon containing photocurable formulation has a viscosity; and whereinthe viscosity of the carbon containing photocurable formulation is inthe range of 10 millipascalsecond to 300 millipascalsecond at about 25°C.
 15. The carbon containing photocurable formulation of claim 1,wherein the carbon containing photocurable formulation has a viscosity;and wherein the viscosity of the carbon containing photocurableformulation is in the range of 50 millipascalsecond to 150millipascalsecond at about 25° C.
 16. The carbon containing photocurableformulation of claim 1, wherein the carbon comprises a carbon nanotube;and wherein the carbon nanotube comprises a single-wall carbon nanotube,a double-wall carbon nanotube, a multi-wall carbon nanotube, or acombination thereof; wherein the carbon containing photocurableformulation, when cured, yields a polymer composite with an electricalresistivity lower than or equivalent to 1 ohmcm.
 17. A method ofpreparation of a carbon containing photocurable formulation, comprising:processing a conditioned photocurable mixture at a high shear rate andthereby preparing a carbon containing photocurable formulation; whereinthe conditioned photocurable mixture is prepared by a method comprisingprocessing a photocurable mixture at a low shear rate; wherein thephotocurable mixture comprises a carbon, a photocurable resin, and aphotoinitiator; wherein the high shear rate is equivalent to or higherthan 200,000 s⁻¹; and wherein the low shear rate is lower than 200,000s⁻¹.
 18. The preparation method of claim 17, wherein the conditionedphotocurable mixture is substantially free of any dispersing agent. 19.The preparation method of claim 17, wherein the carbon is substantiallyfree of functional groups that can facilitate dispersion of the carboncompound in the mixture.
 20. The preparation method of claim 17, whereinthe high shear rate is equivalent to or higher than 500,000 s⁻¹.
 21. Thepreparation method of claim 17, wherein the high shear rate isequivalent to or higher than 1,000,000 s⁻¹.
 22. The preparation methodof claim 17, wherein the high shear rate is equivalent to or higher than10,000,000 s⁻¹.
 23. The preparation method of claim 17, wherein thecarbon comprises a nanocarbon, a pyrolytic carbon, a graphite, anactivated carbon, an amorphous carbon, a carbon fiber, or a combinationthereof.
 24. The preparation method of claim 17, wherein the carboncomprises a nanocarbon; and wherein the nanocarbon comprises a carbonnanotube, a graphene, a fullerene, or a combination thereof.
 25. Thepreparation method of claim 17, wherein the carbon comprises a carbonnanotube; and wherein the carbon nanotube comprises a single-wall carbonnanotube, a double-wall carbon nanotube, a multi-wall carbon nanotube,or a combination thereof.
 26. The preparation method of claim 17,wherein the carbon comprises a graphene; and wherein the graphenecomprises a single layer graphene, a double layer graphene, a multilayergraphene, a graphene strip, or a combination thereof.
 27. Thepreparation method of claim 17, wherein the carbon comprises afullerene; and wherein the fullerene comprises a C₆₀, a C₇₀, a C₇₆, aC₇₈, a C₈₄, or a combination thereof.
 28. The preparation method ofclaim 17, wherein the photocurable resin comprises a monomer, oligomeror a polymer of an acrylate, a methacrylate, an epoxy, a urethane, anester, a silicone, a vinyl alcohol, a vinyl acetate, an alkene, aglycerol, a glycol, a ketone, or a combination thereof.
 29. Thepreparation method of claim 17, wherein carbon containing photocurableformulation has a viscosity; and wherein the viscosity of the carboncontaining photocurable formulation is in the range of 1millipascalsecond to 1,000 millipascalsecond at about 25° C.
 30. Thepreparation method of claim 17, wherein carbon containing photocurableformulation has a viscosity; and wherein the viscosity of the carboncontaining photocurable formulation is in the range of 10millipascalsecond to 300 millipascalsecond at about 25° C.
 31. Thepreparation method of claim 17, wherein carbon containing photocurableformulation has a viscosity; and wherein the viscosity of the carboncontaining photocurable formulation is in the range of 50millipascalsecond to 150 millipascalsecond at about 25° C.
 32. Thepreparation method of claim 17, wherein the carbon containingphotocurable formulation, when cured, yields a polymer composite with anelectrical resistivity lower than or equivalent to 100 ohmcm.
 33. Thepreparation method of claim 17, wherein the carbon containingphotocurable formulation, when cured, yields a polymer composite with anelectrical resistivity lower than or equivalent to 10 ohmcm.
 34. Thepreparation method of claim 17, wherein the carbon containingphotocurable formulation, when cured, yields a polymer composite with anelectrical resistivity lower than or equivalent to 1 ohmcm.
 35. Thepreparation method of claim 17, wherein the carbon containingphotocurable formulation, when cured, yields a polymer composite with anelectrical resistivity lower than or equivalent to 0.1 ohmcm.
 36. Thepreparation method of claim 17, wherein the carbon comprises a carbonnanotube, and wherein the carbon nanotube comprises a single-wall carbonnanotube, a double-wall carbon nanotube, a multi-wall carbon nanotube,or a combination thereof; and wherein the carbon containing photocurableformulation, when cured, yields a polymer composite with an electricalresistivity lower than or equivalent to 1 ohmcm.